Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1867—Arrangements specially adapted for the transmitter end
  • H04L1/1887—Scheduling and prioritising arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/1607—Details of the supervisory signal
  • H04L1/1628—List acknowledgements, i.e. the acknowledgement message consisting of a list of identifiers, e.g. of sequence numbers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/1607—Details of the supervisory signal
  • H04L1/1635—Cumulative acknowledgement, i.e. the acknowledgement message applying to all previous messages
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1809—Selective-repeat protocols
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1829—Arrangements specially adapted for the receiver end
  • H04L1/1835—Buffer management
  • H04L1/1841—Resequencing
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1829—Arrangements specially adapted for the receiver end
  • H04L1/1848—Time-out mechanisms
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/1607—Details of the supervisory signal
  • H04L1/1671—Details of the supervisory signal the supervisory signal being transmitted together with control information
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1829—Arrangements specially adapted for the receiver end
  • H04L1/1854—Scheduling and prioritising arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
  • H04L1/1867—Arrangements specially adapted for the transmitter end
  • H04L1/1874—Buffer management
  • H04L1/1877—Buffer management for semi-reliable protocols, e.g. for less sensitive applications like streaming video

Definitions

• the present invention relates to a server and a client for streaming distribution of real-time data such as video and audio via an Internet radio network.
• the present invention relates to a packet retransmission system and a packet retransmission method for performing more reliable communication while placing importance on real time when a packet loss occurs in data transfer with high real time property.
• packets flowing on a network are often lost due to overflow of a node (router) on the network or bit errors in a wireless space.
• a node Router
• bit errors in a wireless space.
• there are conceivable methods such as (1) do nothing, (2) correct or correct an error, and (3) retransmit.
• the video stream has block noise due to packet loss, the audio stream has discontinuous sound, and other media data is normal media. Playback cannot be performed.
• the method of retransmission is usually performed by data communication that does not require real-time processing.
• the TCP protocol uses If an ACK packet is sent to the sender and the ACK packet does not return to the sender, it is a reliable transfer protocol that determines that the packet has not been received and resends it, but waits for the resend packet. Therefore, time is spent for retransmission, and excess ACK packets and an increase in retransmission packets can compress bandwidth and cause congestion.
• multimedia streaming can be played even if all data has not arrived.Therefore, when packets are lost, only important data packets are resent. Or resend it. By retransmitting only important packets, the bandwidth can be used efficiently, and there is no need to wait for unnecessary retransmission of data packets.
• the retransmission method described in Japanese Patent Application Laid-Open No. 9-214507 is a wireless communication method capable of performing real-time communication with assured quality as much as possible.When a packet is lost, retransmission is attempted several times. If it still does not arrive, packets with lower priority are discarded and retransmitted.
• the retransmission method described in Japanese Patent Application Laid-Open No. 11-2846457 is a retransmission control method for connection-established communication that suppresses low-priority communication packets during congestion. Set the number of retransmissions possible, and reduce the number of retransmissions when retransmission is performed by 1.If the number of retransmissions becomes 0, stop communication for that connection and secure as much high-priority bandwidth as possible. Is what you do.
• RTP Real-Time Transport Protocol
• the method of performing error correction and correction has a problem that the load on the receiving side is increased and congestion is further deteriorated due to redundant data for performing correction.
• the retransmitted packets may be discarded at the source, but the receiving side Has to wait for the retransmission packet or make a retransmission request many times, which results in unnecessary retransmission processing.
• the RTP retransmission function extension proposal which adds a general sequence number to all packets and a priority sequence number to only those packets that can be judged to be retransmitted in case of an important packet or loss.
• the packet communication by the above has the advantage that the receiving side can grasp the priority, but if consecutive buckets are lost, it is not possible to recognize the correct priority, and the retransmission request of all continuously lost buckets is sent. There is a problem that must be done. For example, Fig.
• a packet retransmission system includes a transmitting device that transmits a packet to which a sequence number is added, a receiving device connected to the transmitting device via a network, and a request application unit connected to the receiving device.
• the transmitting device includes:
• a retransmission buffer for storing packets transmitted to the receiving device;
• Retransmission request receiving means for identifying and notifying the sequence number and the maximum (latest) sequence number provided to the requesting application from the retransmission request bucket received from the receiving device;
• Retransmission bucket detecting means for checking whether or not the notified sequence number exists in a retransmission buffer
• Retransmission means for retransmitting all the packets whose presence has been detected by the retransmission packet detection means to the receiving device
• a transmitting device that transmits the packet to which the sequence number is added; a receiving device connected to the transmitting device via a network; and a request application unit connected to the receiving device.
• a receiving device includes:
• a receiving buffer for storing packets received from the transmitting device
• Packet loss detecting means for detecting the loss of the packet
• Retransmission sequence number adding means for issuing an addition command to add a sequence number of a packet in which loss has been detected to a retransmission request list
• Retransmission request list management means for adding the sequence number to the retransmission request list according to the addition command
• Retransmission request transmitting means for transmitting the sequence number stored in the retransmission request list to the transmitting means by putting the sequence number on a retransmission request packet;
• a transmitting device that transmits the packet to which the sequence number is added; a receiving device connected to the transmitting device via a network; and a request application unit connected to the receiving device.
• the transmitting device includes:
• a retransmission buffer for storing packets transmitted to the receiving device, a sequence number from the retransmission request packet received from the receiving device and a maximum (latest) sequence number provided to the request application for notification.
• Retransmission bucket detecting means for checking whether the notified sequence number is present in the retransmission buffer
• Retransmitting means for retransmitting all packets whose presence has been detected by the retransmitted packet detecting means to the receiving device;
• the receiving device includes
• a receiving buffer for storing the packets received from the transmitting device, and receiving means for storing the buckets in the receiving buffer while sorting the buckets received from the transmitting device in sequence number order;
• Packet loss detection means for detecting loss of the packet
• Retransmission sequence number adding means for instructing to add a sequence number of a packet in which loss has been detected to a retransmission request list
• Retransmission request list management means for adding the sequence number to the retransmission request list according to the addition command
• the sequence number stored in the retransmission request list is stored in the retransmission request packet.
• Retransmission request transmitting means for transmitting to the transmitting means on the
• Bucket providing means for supplying a packet in the reception buffer to the request application unit
• Retransmission packet storage means for storing, in a retransmission buffer, a packet to be retransmitted when a specific packet or loss occurs
• Retransmitting means for retransmitting the packet to be retransmitted when the specific packet or the packet is lost
• the receiving device is not limited to
• Retransmission request list management means for switching the state of the packet having the sequence number stored in the packet to the retransmission request state;
• Packet loss detecting means for detecting a sequence number of a packet that has been lost due to a mismatch of a sequence number of a packet in a reception buffer at a packet reception time interval determined from the number of times and the reception time of the packet; and the packet loss detection.
• the sequence number of the bucket in which the means detected the loss Retransmission sequence number adding means for issuing an instruction to be added to the retransmission request list to the retransmission request list management means;
• Retransmission request transmitting means for generating one retransmission request packet carrying a sequence number of one or more packets to be retransmitted present in the retransmission request list, and transmitting the retransmission request packet to a transmitting device,
• the transmission device includes
• Retransmission request receiving means for extracting and notifying the sequence number of the retransmission request packet received from the receiving device
• Retransmission packet detecting means for checking whether a packet of the notified sequence number is stored in a retransmission buffer
• Retransmission request response means for placing the sequence numbers of all the packets detected by the retransmission packet detection means in one retransmission request response bucket and transmitting the sequence numbers to the receiving device;
• Retransmission means for retransmitting the bucket detected by the retransmission packet detection means to the receiving device
• Retransmission request transmitting means for generating one retransmission request packet carrying the maximum (latest) sequence number of the bucket provided by the packet providing means to the request application unit, and transmitting the retransmission request packet to the transmitting device;
• Retransmission buffer deletion means for deleting a packet having a sequence number smaller than the notified maximum sequence number from the retransmission buffer.
• a retransmission request transmitting means for transmitting the retransmission request bucket to a transmitting device
• the transmission device includes
• Retransmission request receiving means for extracting and notifying the sequence number and the maximum sequence number from the retransmission request packet received from the receiving device
• Retransmission packet detecting means for checking whether or not the packet of the notified sequence number is in the retransmission buffer
• Retransmission buffer deleting means for deleting a packet having a sequence number smaller than the notified maximum sequence number from the retransmission buffer; and the retransmission packet detecting means sets the sequence numbers of all the packets detected to be one to one.
• Retransmission request response means for transmitting a retransmission request response packet to the receiving device,
• Retransmitting means for retransmitting a packet detected by the retransmission packet detecting means to the receiving device
• Retransmission request response receiving means for receiving a retransmission request response packet carrying the sequence number of the retransmitted packet from the transmitting device
• Retransmission sequence deletion means for extracting the sequence number from the retransmission request response packet and issuing a deletion instruction to the retransmission request list management means for deleting the same sequence number as the sequence number from the retransmission request list,
• a command to set the state of the retransmission request list to an "ACTIVE" state which means that a packet having the sequence number remaining in the retransmission request list was requested to be retransmitted but will not be retransmitted from the transmitting apparatus in the future.
• the payload (data) of one or more packets is provided to the requesting application unit, and a sequence number smaller than the sequence number of the packet is deleted from the retransmission request list.
• the payload of the packet having the sequence number (N + 1) following the sequence number (N: N is a natural number) of the previously provided packet is provided within the specified time, and within the specified time. If the packet of the next sequence number (N + 1) does not exist in the receiving buffer or is not inserted, It is provided with a packet providing means for notifying the requesting application unit that the bucket to be provided has been lost.
• the state of the retransmission request list indicates that the packet of the sequence number stored in the retransmission request list has already been retransmitted to the transmitting device, but will not be retransmitted from the transmitting device in the future. " If the sequence number of the packet to be provided to the requesting application section is in the above-mentioned retransmission request list in the "ACTIVE" state, it is determined that retransmission is not performed even if a retransmission request is made, and the packet is immediately provided without waiting for the specified time. It is provided with a bucket providing means for notifying the requester that a packet to be lost has been lost.
• a packet between transmission and reception when a packet is lost in packet communication in which a general sequence number given to all packets and a priority sequence number given to a specific packet or a packet to be retransmitted when lost are added.
• a general sequence number given to all packets and a priority sequence number given to a specific packet or a packet to be retransmitted when lost are added.
• the transmitting device is
• Retransmission packet storage means for storing in the retransmission buffer the packet to be retransmitted when the specific packet or the packet is lost,
• Retransmitting means for retransmitting the packet to be retransmitted when the specific packet or the loss
• a retransmission list for storing a general sequence number of a packet to be retransmitted is generated, and retransmission list management means for adding and deleting the general sequence number is provided.
• a retransmission sequence number deletion unit that issues an instruction to delete the general sequence number from the retransmission list to a retransmission list management unit;
• Packet loss detection means for detecting, from the general sequence number and the priority sequence number, a specific sequence having a high priority and a general sequence number of a packet to be retransmitted at the time of loss,
• Retransmission request transmitting means for generating one retransmission request packet carrying one or more general sequence numbers present in the retransmission list, and transmitting the retransmission request packet to a transmitting device;
• the transmission device includes
• Retransmission request receiving means for extracting and notifying the general sequence number from the retransmission request bucket received from the receiving device,
• Retransmission packet detecting means for checking whether a packet of the notified general sequence number is in a retransmission buffer,
• Retransmitting means for retransmitting a packet having a general sequence number whose presence has been detected by the retransmitting packet detecting means to the receiving device;
• Retransmission request transmitting means for generating one retransmission request bucket carrying the maximum (latest) general sequence number of the bucket provided by the bucket providing means to the request application unit, and transmitting the retransmission request packet to a transmitting device;
• the transmitting device is:
• Retransmission request receiving means for extracting and notifying the maximum general sequence number from the retransmission request bucket received from the receiving device
• Retransmission buffer deleting means for deleting a packet having a general sequence number smaller than the notified general sequence number from the retransmission buffer.
• the transmission device includes
• Retransmission request receiving means for extracting and notifying the general sequence number and the maximum general sequence number from the retransmission request packet received from the receiving device
• Retransmission buffer deletion means for deleting a packet having a general sequence number smaller than the notified maximum general sequence number from the retransmission buffer, Retransmission packet detecting means for checking whether or not the packet of the notified general sequence number is in the retransmission buffer;
• Resending means for resending the packet of the general sequence number whose presence has been detected by the retransmission packet detecting means to the receiving device;
• one or more buckets are provided to the requesting application unit with a pay mouth (de-night), and are smaller than the general sequence number of the packet.
• the general sequence number is deleted from the retransmission list, and the pay port of the bucket of the general sequence number (N + 1) following the general sequence number (N: N is a natural number) of the previously provided packet is designated. If the packet with the general sequence number (N + 1) does not exist in the reception buffer or is not inserted in the reception buffer within the specified time, it is assumed that the packet to be provided has been lost. It has a bucket providing means for notifying the requesting application unit.
• the apparatus is provided with a packet providing means for performing packet loss detection and retransmission request transmission several times within the designated time.
• the transmitting device includes
• Priority is given to n (n is a natural number) packets in the vicinity of an arbitrary packet. Priority information to be assigned to a high specific packet or a packet to be retransmitted when lost is added to the bucket p for each m packets (m ⁇ n .: m and n are natural numbers), and the values of n and m are added to the network. Priority information adding means determined from the congestion situation of
• the receiving device is not limited to
• Packet loss detecting means for detecting, from the degree information, a specific bucket having a high priority in which a loss has occurred and a sequence number of a packet to be retransmitted when the loss has occurred.
• a packet retransmission method includes a transmitting apparatus for transmitting a packet to which a sequence number is added, a receiving apparatus connected to the transmitting apparatus via a network, and a request connected to the receiving apparatus.
• the transmitting device includes:
• a retransmission buffer for storing packets transmitted to the receiving device, and a retransmission for identifying and notifying the sequence number and the maximum (latest) sequence number provided to the requesting application from the retransmission request bucket received from the receiving device.
• a transmitting device that transmits the packet to which the sequence number is added; a receiving device connected to the transmitting device via a network; and a request application unit connected to the receiving device.
• a receiving device includes:
• a receiving buffer for storing packets received from the transmitting device
• a retransmission request transmission step for transmitting the sequence number stored in the retransmission request list to the transmission step with the retransmission request packet put on the retransmission request packet; and providing a packet for supplying the packet in the reception buffer to the request aggregation unit.
• a transmitting device that transmits the packet to which the sequence number is added; a receiving device connected to the transmitting device via a network; and a request application unit connected to the receiving device.
• the transmitting device includes: A retransmission buffer for storing packets transmitted to the receiving device, and a retransmission for identifying and notifying the sequence number and the maximum (latest) sequence number provided to the requesting application from the retransmission request packet received from the receiving device.
• the receiving device includes
• a receiving buffer for storing the packets received from the transmitting device; a receiving step of storing packets in the receiving buffer while sorting the packets received from the transmitting device in sequence number order;
• a packet loss detecting step for detecting, a retransmission sequence number adding step for instructing to add a sequence number of the bucket in which the loss is detected to a retransmission request list,
• a retransmission request transmission step for transmitting the sequence number stored in the retransmission request list to the transmission step with the retransmission request packet put thereon, and a packet for supplying the packet in the reception buffer to the request application unit.
• the receiving device is not limited to
• the method After receiving the specific packet or the packet to be retransmitted at the time of the loss, the method includes a receiving step of storing the packet to be retransmitted at the time of the specific packet or the loss in the reception buffer while sorting in order of the sequence number. is there.
• a retransmission request list that stores the sequence number of the bucket that is currently requesting retransmission and the sequence number of the packet that requests retransmission at the time of the next retransmission request, adds and deletes sequence numbers, and generates a retransmission request list.
• a retransmission request list management step for switching the state of the packet of the sequence number stored in the retransmission request state to the retransmission request state.
• Sequence of one or more buckets to be retransmitted present in the retransmission request list A retransmission request transmitting step of generating one retransmission request packet carrying a number, and transmitting the retransmission request packet to a transmitting device,
• the transmission device includes
• a retransmission request transmitting step for generating one retransmission request packet on which the maximum (latest) sequence number of the packet provided by the packet providing step is provided to the requesting application unit, and transmitting the retransmission request packet to a transmitting device;
• the transmission device includes
• a retransmission request receiving step for extracting and notifying the maximum sequence number from the retransmission request bucket received from the receiving device
• a retransmission request transmission step for generating a retransmission request packet on which a packet number and a maximum (latest) sequence number of a packet provided to the request application unit by the packet providing step are added, and transmitting the retransmission request packet to a transmitting apparatus.
• the transmission device includes
• the receiving device It is provided with. Also, the receiving device
• a retransmission sequence deletion step for taking out the sequence number from the retransmission request response packet and issuing a deletion instruction to the retransmission request list management step to delete the same sequence number as the sequence number from the retransmission request list;
• An instruction to set the state of the retransmission request list to the "ACTIVE" state which means that a packet having the sequence number remaining in the retransmission request list was requested to be retransmitted but is not retransmitted from the transmitting apparatus in the future.
• one or more packet payloads are provided to the requesting application unit, and a sequence number smaller than the sequence number of the packet is set in the retransmission request list. And provides the paying port of the packet of the sequence number (N + 1) following the sequence number (N: N is a natural number) of the previously provided packet within the designated time, and If the packet of the next sequence number (N + 1) does not exist in the reception buffer or is not inserted within the designated time, a packet notifying the request application section that the packet to be provided has been lost. It is provided with a providing step.
• a packet providing step is provided in which packet loss detection and retransmission request transmission are performed once or more within the specified time. Also, the receiving device
• the status of the retransmission request list indicates that a packet with the sequence number stored in the retransmission request list has already been requested to be retransmitted to the transmitting device, but will not be retransmitted from the transmitting device in the future.
• the "ACTIVE" state if the sequence number of the packet to be provided to the request advertisement section is in the retransmission request list, it is determined that retransmission is not performed even if a retransmission request is made, and immediately without waiting for the specified time.
• a packet providing step for notifying the requester that the packet to be provided to the client has been lost.
• the packet between the sending and receiving when the packet is lost in the packet communication in which the general sequence number given to all the packets and the priority sequence number given to the specific packet or the packet to be retransmitted when the packet is lost are added.
• the general sequence number given to all the packets and the priority sequence number given to the specific packet or the packet to be retransmitted when the packet is lost are added.
• the transmitting device is
• the receiving apparatus After receiving the specific packet or the packet to be retransmitted at the time of loss, the receiving apparatus stores a packet to be retransmitted at the time of the specific packet or the loss in a reception buffer while sorting in order of general sequence number. It is provided.
• a retransmission list for storing a general sequence number of a packet to be retransmitted is generated, and a retransmission list management step for adding and deleting the general sequence number is provided.
• a retransmission sequence number deletion step for issuing an instruction to delete the general sequence number from the retransmission list to a retransmission list management step;
• a packet loss detection step of detecting a specific packet having a high priority that caused the loss and a general sequence number of a packet to be retransmitted when the loss occurs;
• the transmission device includes
• the receiving device It is provided with. Also, the receiving device
• the transmission device includes
• a retransmission request receiving step for taking out and notifying the maximum general sequence number from the retransmission request packet received from the receiving device
• One retransmission request packet is generated by adding one or more general sequence numbers present in the retransmission list and the maximum (latest) general sequence number of the packet provided to the requesting application unit by the packet providing step.
• the general sequence number from the retransmission request packet received from the receiving device a retransmission request receiving step of extracting and notifying the maximum general sequence number
• the payload (data) of one or more packets is provided to the requesting application unit, and a general sequence number smaller than the general sequence number of the packet is provided from the retransmission list.
• the method includes a packet providing step of detecting packet loss again and transmitting the retransmission request several times within the designated time.
• the requesting application section does not make a retransmission request and waits for a specified time without missing a packet to be provided. It is provided with a packet providing step for notifying the user.
• priority information to be assigned to a specific high-priority packet or a packet to be retransmitted in case of loss is assigned every m packets (m ⁇ n: m , N are natural numbers) and added to bucket p
• the receiving device is not limited to
• FIG. 1 is a configuration diagram of a retransmission system according to Embodiment 1,
• FIG. 2 is a flowchart of the transmitting apparatus according to the first embodiment
• FIG. 3 is a flowchart of bucket receiving of the receiving apparatus according to the first embodiment.
• FIG. 4 is a flowchart of a retransmission request list management process of the receiving device according to the first embodiment
• FIG. 5 is a flowchart of the packet loss detection processing of the receiving apparatus according to the first embodiment
• FIG. 6 is a flowchart of receiving a retransmission request response of the receiving apparatus according to the first embodiment.
• FIG. 7 is a flowchart of providing a packet of the receiving apparatus according to the first embodiment;
• Fig. 8 shows an example of bucket loss and packet loss detection processing in the first embodiment.
• FIG. 9 shows a retransmission system and a packet transfer system according to Embodiment 2. Configuration diagram of the system,
• FIG. 10 is a flowchart of a transmitting apparatus according to the second embodiment.
• FIG. 11 is a flowchart of an example 1 of packet reception of the receiving apparatus according to the second embodiment.
• FIG. 12 is a flowchart of Example 2 of packet reception of the receiving apparatus according to Embodiment 2,
• FIG. 13 is a flowchart of a retransmission request list management process of the receiving device according to the second embodiment
• FIG. 14 is a flowchart of a packet loss detection process of the receiving device according to the second embodiment
• FIG. 15 is a flowchart showing a flow of providing a packet of the receiving apparatus according to the second embodiment.
• Fig. 16 shows an example of packet loss and bucket loss detection processing in the second embodiment.
• FIG. 17 is a configuration diagram of a retransmission system and a packet transfer system according to Embodiment 3,
• Figure 18 shows an example of a bucket with priority information added.
• FIG. 19 is a flowchart showing the operation of the bucket loss detecting means of the receiving apparatus according to the third embodiment.
• FIG. 20 is an example of packet loss and packet loss detection means according to the third embodiment.
• Embodiment 1 Embodiment 1
• FIG. 1 is a bucket retransmission system according to Embodiment 1 of the present invention
• FIG. 3 is a configuration diagram of a packet transfer system, showing retransmission of a packet between transmission and reception and packet transfer when a packet in a packet communication with a sequence number added is lost.
• the retransmission system and the packet transfer system according to the first embodiment are transmitted from a transmission apparatus 101 via a network 104 such as an Internet radio network or the like, a transmission apparatus 101 for transmitting a packet, and a network 104.
• the receiving device 102 receives the received packet, and the requester (application) 103 requests the packet data from the receiving device 102.
• transmitting apparatus 101 stores retransmission packet storing means 105 for storing only packets to be retransmitted among the packets transmitted to receiving apparatus 102 in a retransmission buffer, and retransmission request packets from receiving apparatus 102.
• the sequence number of the packet requested to be retransmitted is received from the retransmission request packet, and the maximum sequence number provided to the requester is taken out to the retransmission packet detection means 107 (this maximum sequence number means the latest packet sequence number).
• Retransmission request receiving means 106 for notifying the retransmission buffer deletion means 120 to the retransmission buffer 120, and retransmission for deleting a packet having a sequence number smaller than the maximum (latest) sequence number provided to the requester 103 from the retransmission buffer. Sequence number notified by the retransmission request receiving means 106 from the transmission buffer deletion means 120 and the retransmission buffer or evening buffer.
• Retransmission packet detection means 107 for detecting, retransmission request response means 108 for transmitting all the sequence numbers detected by retransmission packet detection means 107 to one retransmission request response packet and transmitting to reception apparatus 102, and retransmission It has retransmission means 109 for retransmitting the bucket of the sequence number detected by the bucket detection means 107 to the receiving device 102. Also, the receiving apparatus 102 receives the packet from the transmitting apparatus 101, and stores the bucket in the receiving buffer while sorting the packets in order of the sequence number, and makes a retransmission request at the next retransmission request.
• the retransmission request list management means 115 adds and deletes sequence numbers and performs state transition of the retransmission request list, and the number of times and time of reception of packets
• Packet loss detection means 111 that detects the sequence number of a packet that has been lost due to inconsistency in the sequence number of the packet in the reception buffer at the packet reception interval determined from the packet loss and packet loss detection means 111 that detects the packet loss.
• the retransmission request notifying means 113 which issues a command to set the state to "READY" meaning that it is not known whether or not the packet is retransmitted, to the retransmission request list management means 115, and the packet loss detecting means 111, retransmit at intervals at which packet loss detection is performed.
• the retransmission request transmitting means 114 for transmitting a plurality of sequence numbers present in the request list to one retransmission request packet and transmitting the same to the transmitting device 101, and receiving the retransmission request response packet from the transmitting device 101 from the retransmission request response packet.
• Retransmission request response receiving means 116 for notifying the sequence number of the retransmitted packet to retransmission sequence number deleting means 117, and retransmission for sending the sequence number deletion instruction notified by retransmission request response receiving means 116 to the retransmission request list
• the sequence number deletion means 117 and the status of the retransmission request list are indicated by the sequence number in the retransmission request list.
• the retransmission request response notifying means 118 which issues to the retransmission request list management means 115 an instruction to set the status to "ACTIVE" meaning that the transmission request has not been retransmitted from the transmitting apparatus 101, and It has a packet providing means 119 for providing one or a plurality of packet payouts to the requester (application) 103 from among the packets stored in the application.
• FIG. 2 is a flowchart for explaining the transmitting device
• FIGS. 3, 4, 5, 6, and 7 are flowcharts for explaining the receiving device
• FIG. FIG. 4 illustrates a processing flow from reception of a packet by the receiving means 110 to a request of the retransmission request by the retransmission request transmitting means 114, and FIG.
• FIG. 4 illustrates a processing flow of the retransmission request list management means 115 of the receiving apparatus 102.
• FIG. 5 illustrates the processing flow of the packet loss detecting means 111 of the receiving apparatus 102, and
• FIG. 6 illustrates the processing flow when the retransmission request response packet is received by the retransmission request response receiving means 116.
• FIG. 7 illustrates the processing flow when a requester (an abbreviated) requests the provision of a packet by the packet provision means 119.
• transmitting apparatus 101 transmits a packet to receiving apparatus 102 (step S202).
• Transmitting apparatus 101 stores the transmitted packet in the retransmission buffer (step S203). At this time, all packets may be stored in the retransmission buffer 201, or only important packets to be retransmitted may be stored in the retransmission buffer 201.
• the bucket with the smallest sequence number is deleted from the retransmission buffer 201 (step S205).
• the receiving means 110 of the receiving device 102 Upon receiving the packet from the transmitting device 101 as shown in FIG. 3 (step S301), the receiving means 110 of the receiving device 102 stores the received packets in the receiving buffer while sorting them in order of sequence number (step S301).
• Step S the packet loss detecting means 11 1 checks for missing packets.
• This check processing is called packet loss detection processing.
• the interval at which the packet loss detection means 111 performs the packet loss detection processing may be, for example, the sequence number or the time of the last packet that has been previously subjected to the packet loss detection processing (step S306). It is determined from the difference between the stamp and the sequence number or time stamp of the packet received this time (step S303).
• the interval between the sequence numbers for performing the packet loss detection processing (step S306) is Nint, the time stamp interval is Tint, and the packet loss detection means 111 performs the last packet loss detection processing (step S306).
• the receiving means 110 receives the packet received this time. If the sequence number of the packet is equal to or greater than Ncur + Nint, or the time stamp of the received packet is equal to or greater than Tcur + Tint, if the sequence number of After substituting the sequence number of the bucket and the time stamp, the packet loss detection processing (step S306) is performed. As a result, the values of Ncur and Tcur become the last sequence number and timestamp of this new packet.
• Nint and Tint may be fixed values, or may be dynamically determined from the network congestion status.
• Packet loss detection unit 111 sorted received Roh order of sequence number, the 'Uz off ⁇ previous packet loss detection processing (S30 6) the last Pakedzu bets next Pakedzu Bok from the sequence number Ncur Been ( The range up to the packet of the last packet of this time (excluding the Ncur packet), or the range of the time stamp Tcur (the time stamp of the last packet this time) (Excluding the Tcur packet), the sequence missing by checking the consistency of the sequence number Find the number.
• FIG. 5 shows a detailed flow of the bucket loss detection processing (step S306) by the bucket loss detection means 111.
• the packet loss detecting means 111 first sets P in the packet buffer in which the sequence number becomes equal to FSN in the reception buffer (step S502).
• the FSN is the sequence number of the packet next to the last bucket in which the previous packet loss detection was performed.
• Loss is the number of missing buckets
• I is the distance from the FSN
• SN_list is the list of missing packet sequence numbers
• 0 is set as the initial value for Loss and FSN
• blank is set as the initial value in SN—list (Empty list) is set (step S503).
• the sequence number Ncur (the last packet of the current packet) starts from the next packet after the last packet in which the previous packet loss detection processing (S306) was performed.
• Sequence number) up to a packet (excluding Ncur packets), or a packet up to a short stamp Tcur (time stamp of the last packet of this time) (but a Tcur packet) ) Is compared with the sequence number of the packet stored in the pointer P of the reception buffer and FSN + I (step S505).
• step S505 if the sequence number of the packet stored in the FSN + I is the same as the sequence number of the packet stored in the boyfriend P, the packet of the sequence number FSN + I is received without any loss c.
• step S506 I is incremented (step S506), and the pointer of the next packet is set in P (step S506). If it is determined in step S505 that the sequence numbers of the packets stored in the FSN + I and the buses P are not equal, the process proceeds to step S507. If FSN + I is smaller than the sequence number of the packet stored in the bus P (step S507), it means that the sequence number FSN + I is missing. Therefore, FSN + I is added to SNJist (step S508), and I and Loss are incremented (step S509).
• step S504 that is, the range from the packet following the last packet in which the previous packet loss detection process (S306) was performed to the packet of sequence number Ncur (the sequence number of the last packet of this time) ( However, this sequence number is compared in the range up to the packet of the timestamp Tcur (the timestamp of the last packet of this time) (excluding the packet of the Ncur), but excluding the packet of the Tcur).
• step S510 a value is added to the FSN, and the FSN is set as a start sequence number for the next packet loss detection process (step S511).
• the number in the SN_list is the sequence number of the missing bucket in the range, and the loss is the number of the missing packets.
• Fig. 8 shows an example of the reception buffer where a packet loss has occurred and the result of executing the packet loss detection processing.
• 802 indicates the state of FSN, Ncur, I, Loss, Snjist at the time of the Nth packet loss detection processing
• 803 represents the state of FSN, Ncur, I, Loss, and Snjist at the time of the N + 1th packet loss detection processing.
• 0 is set to Loss as an initial value
• 0 is set to I as an initial value
• 0 is set to SN-list as an initial value (step S503).
• the process branches to S506, where I is incremented by one and the pointer P is also incremented by one to set the pointer of the next packet (step S506). As a result, 1 1, and the sequence number stored in the pointer P is 9.
• Step S505 the sequence number stored in the pointer P is compared again with the sequence number stored in the pointer P.
• Is set step S506).
• 1 2
• step S505 the process returns to the loop, and again compares the FSN + I with the sequence number stored in the pointer P (step S505).
• the sequence number stored in the boyfriend P is 2 1 2
• Is incremented by 1 and the pointer P is also incremented by 1 to set the next packet packet (step S506).
• 1 5
• the sequence number stored in the pointer P becomes 15.
• step S505 the process returns to the loop, and again compares the FSN + I with the sequence number stored in the pointer P (step S505).
• step S507 the result of the comparison is “sequence number stored in the pointer P by FSN + 1”, and the flow branches to step S508.
• the value of SN_list changes from "11, 13" to "11, 13, 13, 14".
• Loss is also incremented by one (step S509).
• step S306 After executing the packet loss detection processing (step S306), if Loss> 0, it means that a packet loss has been detected.
• step S
• the retransmission request list management unit 115 that has received the addition command adds the SNJist sequence number to the retransmission request list (steps S402 to S407). However, double registration is not performed. However, if all of the sequence numbers in the SN_list are in the "ACTIVE" retransmission request list and none of them can be added to the retransmission request list, the following retransmission request notification processing and retransmission request transmission processing are performed. Absent.
• retransmission request notifying means 113 issues an instruction to retransmission request list managing means 115 to change the state of the retransmission request list to the "READY" state (step S308).
• the retransmission request list in the "READY" state is a list of sequence numbers for which retransmission requests are made, but it is not known whether all sequence numbers are retransmitted.
• the retransmission request list management unit 115 that has received the READY command sets the retransmission request list to a “READY” state (steps S402, S03, and S412).
• the retransmission request transmitting means 114 requests the transmitting apparatus 101 to retransmit the sequence numbers in the retransmission request list (step S309).
• the sequence number of the retransmission request list and the maximum (latest) sequence number of the packet provided to the requester (application) 103 at that time are placed in one retransmission request packet, and the retransmission request packet is transmitted.
• the information is transmitted to the device 101 (step S310).
• the retransmission request receiving means 106 of the transmitting apparatus 101 receives the retransmission request packet as shown in FIG. 2 (step S207), and receives the sequence number and the requester (application) from the retransmission request packet.
• the maximum (latest) sequence number provided to 103 is identified (steps S208, S209).
• the retransmission buffer deleting means 120 does not need to request retransmission any more for packets having a sequence number smaller than the maximum (latest) sequence number in the retransmission buffer 201 provided to the requester (application) 103. because, to remove these Pakedzu door (step S 210) o
• retransmission packet detecting means 107 searches the retransmission buffer and detects a sequence number equal to the sequence number requested for retransmission (step S211). This sequence number is the sequence number of the packet to be retransmitted, and is called the retransmission sequence number.
• retransmission request response means 108 generates one retransmission request response packet carrying the retransmission sequence number detected by retransmission packet detection means 107, and transmits the retransmission request response packet to receiving apparatus 102 (step S 212) 0
• retransmitting means 109 retransmits the packet of the retransmission sequence number to receiving apparatus 102 (step S213).
• the retransmission request response receiving means 116 of the receiving device 102 Upon receiving the retransmission request response bucket carrying the retransmission sequence number from the transmission device 101 as shown in FIG. 6 (step S601), the retransmission request response receiving means 116 of the receiving device 102 receives the retransmission sequence number from the retransmission request response bucket. Is identified (step S602).
• retransmission sequence number deletion means 117 issues a deletion command to retransmission request list management means 115 so as to delete from the retransmission request list the retransmission sequence numbers of packets for which retransmission requests have become unnecessary due to successful reception. (Step S603).
• the retransmission request list management means 115 that has received the delete command deletes the retransmission sequence number from the retransmission request list as shown in FIG. 4 (steps S402, S403, S408 to S411). Therefore, the sequence number remaining in the retransmission request list is lost, so that a retransmission request was made, but this is the sequence number of a packet that is not retransmitted from transmitting apparatus 101.
• the retransmission request response notifying means 118 issues a command to the retransmission request list management means 115 so as to change the retransmission request list to the "ACTIVE" state as shown in FIG. 6 (step S604).
• the retransmission request list management means 115 Upon receiving the ACTIVE command, the retransmission request list management means 115 changes the retransmission request list to the "ACTIVE" state as shown in FIG. 4 (steps S402, S403, S413).
• the retransmission request list in the "ACTIVE" state means a sequence number that is not retransmitted from the transmitting device even if a retransmission request is made.
• the requester (application) 103 requests the payload of the packet received by the receiving device 102.
• the packet providing means 119 of the receiving apparatus 102 transmits the packet provided previously by the waiting time.
• the bucket providing means 119 notifies the requester (application) 103 that the bucket of Tnext has been lost.
• the requester (abbreviation) 103 requests the payload of the bucket and the allowable waiting time from the request to the provision of the paying port (step S702), as shown in FIG.
• the current time is set to Tstart (step S703), and it is checked whether or not the packet of the sequence number Tnext exists in the reception buffer (step S704). If there is a packet of Tnext in the reception buffer, the payload of the packet of Tnext is provided (step S705).
• step S706 If there is no packet of Tnext in the reception buffer, the time is checked to see if the current time has exceeded the waiting time (step S706).
• the requester (application case) 103 is notified (step S709). If not, it is checked whether or not the sequence number Tnext is on the retransmission request list (step S707).
• Tnext is in the retransmission request list and the retransmission request list is in the "ACTIVE" state (step S708), it means that even if a retransmission request is made from transmitting apparatus 101, it will not be retransmitted.
• the requester (application) 103 is notified that the is lost (step S709). If Tnext is not in the retransmission request list, Tnext is set in the FSN (step S711), the sequence number of the latest packet currently received is set in Ncur (step S712), and the latest received packet is set in Tcur.
• a packet time stamp is set (step S713), after which a packet loss detection process (step S714), a retransmission sequence number addition process (step S715), and a retransmission request response notification process (step S716) Using the retransmission request transmission process (steps S717 and S718), the Tnext retransmission request is made again, the latest packet loss is detected, and the retransmission request is made at the same time.
• the waiting time When the waiting time is set to 0, it checks only whether there is Tnext in the receive buffer, and if not, does not request retransmission of the Tnext packet and immediately confirms that the Tnext packet was lost. Notify the requester (application) 103. Conversely, if the waiting time is set to infinite time, if there is no Tnext packet in the receive buffer, retransmission request is made many times, and waits until the Tnext packet is retransmitted.
• the retransmission request transmitting means transmits the retransmission request packet, it waits for the retransmission request interval Tr (step S720), and checks again whether there is a Tnext packet in the reception buffer. Tr may be changed each time a retransmission request is made.
• steps S719, S720, and S721 a sleep time for the waiting time is created.
• step S720 sleep (delay) is performed for 2 seconds. Therefore, two seconds later, the reception buffer is checked and the packet loss detection processing is performed again (step S714).
• the reception buffer can be checked and the packet loss detection process (step S714) can be performed periodically within the permitted time, that is, during the waiting time.
• the reception buffer is also checked. However, since the timeout is determined in step S706, the process is not performed until the packet loss detection process.
• the packet data can be provided within the waiting time.
• a retransmission packet storage unit by providing a retransmission packet storage unit, a retransmission request reception unit, a retransmission bucket detection unit, and a retransmission unit in a transmission device, only important packets with high priority can be retransmitted. Waste of the network load due to the retransmission processing can be minimized, and the transmission capacity of high-priority packets can be ensured even during network congestion.
• the retransmission packet storage means saves only important packets with high priority in advance in the retransmission buffer instead of selecting the packet to be retransmitted with high priority from among all the transmitted packets. As a result, it is possible to reduce the processing load for searching for retransmitted packets, minimize the retransmission buffer of the transmitting device, and reduce waste of resources.
• the receiving means shuffles the packet received from the transmitting device. -Since the data is stored in the reception buffer while sorting in the order of the can number, when the packet loss detection process detects a lost bucket from among the packets in the reception buffer, it can be detected at high speed.
• identification of the sequence number making the retransmission request and identification of the sequence number of the retransmitted packet are performed. It can be done easily.
• a retransmission request for a plurality of packet losses can be made. Also, in a transmitting device that retransmits only important packets with high priority, the receiving device can identify the sequence number of the packet retransmitted from the transmitting device, thereby eliminating unnecessary retransmission requests for packets that are not retransmitted. Or waiting for the packet to be retransmitted, realizing a more real-time transfer method.
• the retransmission request receiving means and the retransmission buffer deleting means it is possible to reduce the number of retransmission buffers of the transmission device.
• retransmission packet detection means and retransmission means only packets with high priority to be retransmitted can be retransmitted, and congestion worsens by transferring the minimum number of retransmission packets even in a network congestion state. Can be prevented.
• the retransmission request response means the sequence number of a packet having a higher priority to be retransmitted can be recognized by the receiving apparatus, and it is possible to prevent the receiving apparatus from making useless retransmission requests.
• the receiving device can make useless retransmission requests for low priority packets that are not retransmitted from the transmitting device. Can be prevented.
• the requester application
• the requester can set a waiting time for each packet, and by that time the provision of a packet payload or the occurrence of a packet loss. Get notifications.
• the packet loss detection means and the retransmission request sent by the retransmission request transmission means are made several times during the waiting time even when a request is made from the requester (application).
• the packet loss detection means and the retransmission request are made several times during the waiting time even when a request is made from the requester (application).
• Embodiment 2 by providing a packet loss detecting means in the receiving device for accurately recognizing the priority of the bucket in which the loss has occurred from the sequence number mismatch and the priority information, waste of low priority packets that are not retransmitted is provided. This can prevent unnecessary retransmission requests, and reduce network waste and retransmission bucket detection processing load on the transmitting device.
• FIG. 9 is a block diagram of a bucket retransmission system and a packet transfer system showing Embodiment 2 of the present invention.
• the general sequence numbers assigned to all packets and the method of retransmission when important packets or loss are found.
• Priority sequence number assigned only to packets judged to be good It shows retransmission between transmission and reception and packet transfer when a packet is lost in the bucket communication.
• the retransmission system and the packet transfer system according to the second embodiment include a network 904 such as an in-network / wireless network, a transmission device 901 for transmitting a packet, and a transmission device via the network 904.
• the receiving apparatus 902 includes a receiving apparatus 902 that receives a packet transmitted from the apparatus 901, and a requester (application) 903 that requests the packet data from the receiving apparatus 902.
• transmitting apparatus 901 receives retransmission packet storing means 905 for storing only packets to be retransmitted among the packets transmitted to receiving apparatus 902 in a retransmission buffer, and receives a retransmission request packet from receiving apparatus 902. Then, the general sequence number of the retransmitted packet is extracted from the retransmission request packet, and the maximum general sequence number provided to the requester (this maximum general sequence number is Retransmission request receiving means 906 for notifying the retransmission buffer deletion means 907 of the general sequence number (meaning the general sequence number), and a general sequence number smaller than the maximum (latest) general sequence number provided to the requester 903.
• Retransmission buffer deleting means 907 for deleting the packet of the retransmission buffer from the retransmission buffer, and retransmission request receiving means 906 from the retransmission buffer.
• a retransmission packet detecting means 908 for detecting the knowledge has been commonly sequence number, and a retransmission means 909 to retransmit the packets of the general sequence number detected at the same retransmission Baketsuto detecting means to the receiving device 902.
• the receiving device 902 receives the packet from the transmitting device 901 and stores the packet in a receiving buffer while sorting the packets in the order of the general sequence number.
• the receiving device 902 also performs a retransmission request at the time of the next retransmission request.
• Retransmission list management that adds and deletes general sequence numbers in the retransmission list that stores the general sequence number of the packet and the packet that is currently requesting retransmission.
• Means 915 if the general sequence number of the received packet is in the retransmission list, retransmission sequence number deletion means 911 that issues an instruction to delete the general sequence number to retransmission list management means 915, and the number of times and time of packet reception Each time an important packet is lost due to the determined packet reception interval or mismatch of the priority sequence number, the packet in the receive buffer is lost due to the mismatch between the general sequence number and the priority sequence number of the received packet.
• the additional means 913 and the packet loss detection means 912 perform packet loss detection. At this time, a plurality of general sequence numbers present in the retransmission list are added to one retransmission request packet and transmitted to the transmission device 901 from the retransmission request transmission means 914 and the packet stored in the reception buffer. There is provided a packet providing means 916 for providing one and a plurality of packet payouts to a requester (application) 903.
• FIG. 10 is a flowchart for explaining the transmitting device
• FIGS. 11, 12, 13, 14, and 15 are flowcharts for explaining the receiving device.
• FIGS. 11 and 12 explain two examples of the processing flow from when the receiving means receives a packet to when the retransmission request transmitting means makes a retransmission request
• FIG. 13 shows the retransmission of the receiving apparatus.
• FIG. 14 illustrates the processing flow of the packet loss detection means 912 of the receiving device
• FIG. 15 illustrates the processing flow of the packet loss detection means 912 of the receiving device. This explains the processing flow when a request to provide a packet is made.
• transmitting apparatus 901 transmits a packet to receiving apparatus 902 (step S1001).
• Transmission device 901 retransmits the transmitted packet Save it in the buffer (step S1002).
• all packets may be stored in the retransmission buffer 1005, or only important packets to be retransmitted may be stored in the retransmission buffer.
• step S1003 the packet with the smallest general sequence number is deleted from the retransmission buffer 1005 until the size of the retransmission buffer 1005 becomes equal to or less than the maximum number of packets or the maximum time.
• the receiving means 910 of the receiving device 902 sorts the received packet into the receiving buffer while sorting it in the order of the general sequence number. Save it (Steps S1102, S1202)).
• the retransmission sequence number deletion means 911 checks whether or not the received packet is on the retransmission list every time a bucket is received. If the general sequence number of the received packet is on the retransmission list (steps S1103 and S1203), this received packet means the retransmitted packet, and since there is no need to request this retransmission any more, A delete command is issued to the retransmission list management means 915 so as to delete the general sequence number of the received bucket from the retransmission list (steps S1104 and S1204).
• the bucket loss detecting means 912 checks whether the bucket is missing. This check processing is called packet loss detection processing.
• packet loss detection processing Two examples of packet loss detection processing performed by the packet loss detection means 912 after receiving a packet will be described. As shown in the flow chart of Example 1 in FIG. 11, the interval at which the packet loss detection means 912 performs the packet loss detection processing (step S1108) is, for example, the previous packet It is determined from the difference between the general sequence number and time stamp of the last packet that has been subjected to the packet loss detection processing (step S1108) and the general sequence number and evening stamp of the packet received this time (step S1105).
• the general sequence number for performing the packet loss detection process is Nint
• the time stamp interval is Tint
• the general sequence of the last packet that was previously subjected to the packet loss detection process step S1108
• the general sequence number of the packet received by the receiving unit 910 this time is equal to Ncur + Nint If it is greater than or greater, or the timestamp of the received packet is equal to or greater than Tcur + Tint (step S1105), the general sequence number and time of the packet received this time are stored in Ncur and Tcur.
• a packet loss detecting means is performed (step 1108).
• the values of Ncur and Tcur become the last general sequence number and time stamp of the new packet this time.
• Nint and Tint may be fixed values or may be dynamically determined from the network congestion status.
• the packet loss detecting means 912 sets the general sequence number Ncur (Ncur) from the next packet after the last packet that has been subjected to the packet loss detection processing (step S1108) in the reception buffers sorted in the order of the general sequence number. Range up to the packet of the last packet of this time (general sequence number) (excluding Ncur packet), or range up to the packet of timestamp Tcur (timestamp of this last packet) (Excluding Tcur packets), general sequence number and priority sequence number Check the integrity of packets and detect the loss of high-priority packets to be retransmitted.
• FIG. 14 shows a detailed flow of the packet loss detection processing (step S1108) by the packet loss detection means 111.
• Pakedzu preparative loss detection unit 111 is initially generally the sequence number in the received Badzufa to sets the Boyne evening equal packets and FSN to P (Step S1402) C where, FSN is the last packet This is the general sequence number of the packet next to the last packet in which loss detection was performed.
• the priority sequence number of the packet stored in the bus P is stored in the MPSN (step S1403).
• MPSN means the highest (latest) priority sequence number during the missing bucket search.
• Loss is the number of lost packets
• I is the distance from the FSN
• SNJist is the list of general sequence numbers of lost packets with high priority to be retransmitted
• 0 is set as the initial value for Loss and FSN. Is set to blank (empty list) as the initial value (step 1404).
• the general sequence number Ncur (the last packet of the current packet) in the above-mentioned range shown in step 1405 of the packet loss detection process is applied from the next packet after the last packet for which the previous packet loss detection process (step S1108) was performed.
• the range up to the packet of the general sequence number (excluding the Ncur packet), or the range up to the packet of the time stamp Tcur (the time stamp of the last packet this time)
• the general sequence number of the packet stored in the pointer P of the reception buffer is compared with the FSN + I (step S1406).
• step S1406 if the general sequence number of the packet stored in FSN + I is the same as the general sequence number of the packet stored in Boyne P, the general sequence number; the packet of FSN + I is received without loss Will be. Therefore, the priority sequence number of the packet stored in the pointer P is set in MPSN (step S1407), I is incremented (step S1408), and the pointer of the next packet is stored in P. Set (Step S1410) o In Step S1406, if the FSN + I is not equal to the general sequence number of the packet stored in the bus P, the process proceeds to Step S1409.
• FSN + I is smaller than the general sequence number of the packet stored in the pointer P (step S1409), and if MPSN is smaller than the priority sequence number of the packet stored in the pointer P (step 1411). This means that the packet with the general sequence number FSN + I has been lost, and that packet is a packet with a high priority to be retransmitted. There, FSN + I is added to SN_list (step 1414), and I and Loss are incremented (step 1415).
• step S1411 if the MPSN is not smaller than the priority sequence number of the packet stored in the pointer P (step 1411), the lost packet is a low-priority packet that does not require retransmission, and Therefore, the missing general sequence number is not added to SNJist.
• step S1405 [General sequence number Ncur (general sequence number of the last packet this time) from the next packet after the last packet that performed the previous packet loss detection process (S1108)] Range up to (but not including, Ncur packets), or up to (up to, but not including) Tcur (time stamp of last packet) )],
• step S1416 add I to the FSN and use the FSN as the start general sequence number for the next packet loss detection process (step S1416).
• step S1417) At this time, the number in the SNJist is the general sequence number of the missing packet within the range and the bucket with the highest priority to be retransmitted, and the number of lost packets is the number of missing packets.
• Fig. 16 shows an example of the reception buffer where a packet loss has occurred and the result of executing the packet loss detection processing.
• reference numeral 1602 denotes states of the FSN, Ncm ⁇ I, Loss, and Snjist during the Nth packet loss detection processing.
• 163 represents the state of FSN, Ncur, I, Loss, Sn_list at the time of the (N + 1) -th packet loss detection process.
• the general sequence numbers of the packets in the receive buffer 1601 are:, 8, 9, 10, 12, 15, 16, 18, 19, 22, 23, 24, 25 , 26,..., and the priority sequence numbers are 4, 4, 5, 7, 7, 8, 8, 9, 10, 0, 1, 1, 1, 1, 1, 1, 1, 2,..., respectively.
• the numbers missing from the general sequence number 16 to 23 Is detected.
• three general sequence numbers of 17, 20, and 21 are missing, and these three packets are lost.
• the priority sequence numbers of the general sequence numbers 19 and 22 are 8 and 9, respectively, and the priority sequence number of the general sequence number 22 packet is the general sequence number 19 packet.
• the lost general sequence number 20 and 21 packets may be higher priority packets to be retransmitted, or the general sequence number 22 higher priority packet to retransmit. Therefore, both general sequence numbers 20 and 21 may be low-priority packets that do not require retransmission. In this way, when packets are continuously lost and the priority sequence numbers are not equal before and after that, it is not possible to determine which is the higher priority bucket, so the general sequence numbers of all continuously lost packets are recorded in SL_list. to add.
• 0 is set to Loss as an initial value
• I is set to 0 as an initial value
• SNJist is set to 0 as an initial value (step S1404).
• step S1406 the process returns to the loop, and again compares the FSN + I with the general sequence number stored in the pointer P (step S1406).
• 1 3, MPSN-5, and the general sequence number stored in Boyne P is 12.
• the packet loss detection means 912 detects that the packet of the priority sequence number “11” has been lost.
• 0 is set to Loss as an initial value
• I is set to 0 as an initial value
• SNJist is set to 0 as an initial value (step S1404).
• the process returns to the loop, and again compares the FSN + I with the general sequence number stored in the pointer P (step S1406).
• FSN + I 1 6 +
• step S The flow branches to 1407, and the priority sequence number of the packet stored in the bus P is set to 9 in the MPSN (step S1407), and I is incremented by 1 (step S1408).
• the POINT setting of the next packet is set by incrementing the POINT setting P by one (step S1410).
• step 1108 After the packet loss detection process (step 1108), if Loss> 0, packet loss has been detected, so the retransmission sequence number adding means 913 is registered in the retransmission list management means 915 in the SN_list. It issues an instruction to add the general sequence number of the missing packet (step S1109).
• the retransmission list management unit 915 that has received the addition instruction adds the general sequence number of the SN_list to the retransmission list as shown in FIG. 13 (steps S1302 to S1307). However, double registration is not performed.
• the retransmission request transmitting means 914 makes a request for retransmission of the general sequence number of the retransmission list to the transmitting device 901 (step SlllO, Sllll) o
• the general sequence number of the retransmission list Then, the maximum (latest) general sequence number of the packet provided to the requester (application) 903 at that time is put on one retransmission request packet (step S1110), and this retransmission request packet is transmitted to the transmitting device 901. (Step smi)
• step S1201 to S1203 the operations in steps S1201 to S1203 are the same as those in steps S1101 to S1103 in FIG. 11, and a description thereof will be omitted.
• the priority sequence number RPSN of the reception bucket is compared with the highest priority sequence number MPSN in the reception buffer (step S1205). If RPSN-MPSN> 1, then the priority sequence number becomes discontinuous (step S1205). Therefore, one or more high-priority packets to be retransmitted are always lost.
• a packet having a general sequence number 10 is stored in the reception buffer of FIG. 16 and a packet having a general sequence number 12 has been received.
• the priority sequence number jumps from 5 to 7 and is clearly discontinuous, with RPSN-MPSN> 1 (step S1205). Therefore, one or more packets with high priority to be retransmitted are always lost. In this example, the packet of general sequence number 11 is missing.
• a general sequence number of MSN + 1 to RSN-1 (in this example, a general sequence number of RSN-1)
• An add command is issued to the retransmission sequence number adding means to add the packet of the number 11) to the retransmission list (step S1208). If No in step S1205, that is, if the RPSN and the MPSN are equal or the RPSN is larger by 1, it is not known from the priority sequence number alone whether or not the packet has been lost.
• step S1207 it means that the general sequence number is a continuous gun and there is no packet loss. Therefore, since there is no need to retransmit the packet, the process returns to step S1201 to perform the process of receiving the next packet without performing the retransmission sequence number addition process (step S1201). If RSN—MSN> 1 in step S1207, the general sequence numbers are discontinuous, and one or more high-priority packets to be retransmitted are missing. In order to make a request for retransmission of the packet between the RSNs, the MSN issues an addition command to the retransmission sequence number adding means to add the general sequence number of the RSN to the retransmission list (step S1208).
• the retransmission list management unit 915 that has received the addition command adds the general sequence number of the SN list to the retransmission list as shown in FIG. 13 (steps S1302 to S1307). However, double registration is not performed.
• the retransmission request transmitting unit 914 back to Figure 12, generally the retransmission list, - the cans requests retransmission number to the transmitter 901 (step S1209, Sl210) o General sequence number of this case, the retransmission list Then, the maximum (latest) general sequence number of the packet provided to the requester (application) 903 at that time is put on one retransmission request packet (step S1209), and this retransmission request packet is transmitted to the transmission device 901. Yes (Step S1210) o
• the retransmission request receiving means 906 of the transmitting device 901 receives the retransmission request packet as shown in FIG. 10 (step S1006), and receives the general sequence number requested from the retransmission request packet and the requester (application) 903. Identify the maximum (latest) general sequence number provided to (steps S1007, S1008).
• the retransmission buffer deleting unit 907 needs to request the retransmission of a bucket having a general sequence number smaller than the maximum (latest) general sequence number in the retransmission buffer provided to the requester (application) 903. Since there are no such packets, delete these packets (step 1009).
• retransmission packet detecting means 908 searches the retransmission buffer and detects a general sequence number equal to the general sequence number requested for retransmission (step 1010). This general sequence number is the general sequence number of the high priority bucket to be retransmitted, and is called the retransmission sequence number.
• retransmission means 909 retransmits the packet of the retransmission sequence number to receiving apparatus g 902 (step 1011).
• the requester (application) 903 requests the payout port of the packet received by the receiving device 902.
• the packet providing means 916 of the receiving device 902 receives the packet previously provided by the waiting time.
• the payload of the next packet (general sequence number Tnext) is provided, but the Tnext packet is lost or not retransmitted, so that the Tnext packet's pay packet If the packet cannot be provided, the packet providing means 916 notifies the requester (application) 903 that the packet of Tnext has been lost.
• the bucket providing means 916 requests the packet payload from the requester (application) 103 and the allowable waiting time from the request to the provision of the pay mouth (step). (S1502), the current time is set to Tstart (step S1503), and it is checked whether or not the packet of the general sequence number Tnext is in the reception buffer (step S1504). If there is a packet of Tnext in the reception buffer, the payload of the packet of Tnext is Provide (step S1505).
• Step S1506 If there is no Tnext packet in the reception buffer, a time check is performed to determine whether the current time has exceeded the waiting time (step S1506), and if the time is out, the requester is notified that the Tnext packet has been lost. (Ablation) Notify 903 (Step S1508). If not, it is checked whether the general sequence number Tnext is on the retransmission list (step S1507).
• Tnext is not in the retransmission list, it means that the retransmission request is not transmitted from the transmitting device 901, so the requester (application) 903 is notified of the loss of the Tnext packet (step 1508). ).
• Tnext is on the retransmission list, it means that a retransmission request was made, but the retransmission request packet did not arrive, or the retransmission packet did not arrive.
• Tnext is set to FSN (step 1510)
• the general sequence number of the latest packet received this time is set to Ncur (step 1511)
• the time stamp of the latest packet received this time is set to Tcur (step 1511).
• a retransmission request of Tnext is made again by using the step 1512), the bucket loss detection processing (step S1513), the retransmission sequence number addition processing (step S1514), and the retransmission request transmission processing (steps S1515 and S1516).
• the latest packet loss is also detected, and a retransmission request is made at the same time.
• Example 2 of the packet loss detection method described above when a retransmission request is made every time a packet with a higher priority to be retransmitted is lost, there is no Tnext packet in the reception buffer at the time of the packet providing means. On the other hand, when Tnext is included in the retransmission list, packet loss detection means is not performed, and a request for retransmission of the Tnext packet is immediately made.
• the waiting time When the waiting time is set to 0, only check whether there is Tnext in the receive buffer, and if not, do not request retransmission of the Tnext packet.
• the requester (application) 903 is notified immediately that the packet of Tnext has been lost. Conversely, if the waiting time is set to infinite, if there is no Tnext bucket in the receive buffer, it will make a retransmission request many times and keep waiting for the Tnext bucket to be retransmitted.
• the retransmission request transmitting unit waits for a retransmission request interval Tr (step S1518), and checks again whether there is a Tnext packet in the reception buffer. Tr may be changed each time a retransmission request is made. In steps S1517, S1518, and S1519, the waiting time is created based on the sleep time.
• step S1518 sleep (delay) for 2 seconds. Therefore, after 2 seconds, the reception buffer check and packet loss detection processing are performed again. This allows the reception buffer to be checked and the packet loss detection process to be performed periodically within the allowed time, that is, during the waiting time.
• the configuration of the third embodiment is such that the transmitting apparatus 901 having the configuration of FIG. 9 of the second embodiment transmits important packets in ⁇ packets near a certain bucket ⁇ .
• packet information that can be determined to be retransmitted is added to the packet p every m (m ⁇ n), and n and m are priority information adding means 1705 determined from the network congestion status. Is added.
• means other than the receiving means 1711, the bucket loss detecting means 1713, and the bucket providing means 1717 of the receiving device 1702 are means for performing the same processing as in the second embodiment.
• FIG. 18 shows an example of a packet to which priority information has been added by the priority information adding means 1705.
• the n-th bit from the left indicates the priority of P
• the first bit indicates the priority of the packet with the (n) -th sequence number (P sequence number).
• the value of the k-th bit from the left indicates the priority of the packet whose sequence number is (P sequence number)-1 + k ⁇ Then, in the priority information 1803,
• the first bit from the left is
• the first bit from the left is
• the first bit from the left is
• the first bit from the left is
• the (P sequence number) -n + k-th packet indicates a high-priority packet to be retransmitted, and if 0, a low-priority packet that is not retransmitted.
• the priority information 1804 added to the packet with sequence number 8 indicates that among the packets with sequence numbers 1 to 8, the packets with the higher priority to be retransmitted are sequence numbers 1, 4, 5, and 8 This is 10011001 from the left.
• n pieces of priority information including P of bucket P
• the value of the k-th bit indicates the priority of the packet whose sequence number is (P sequence number) + k—1.
• the third bit sequence number from the left is
• the 8th bit sequence number from the left is
• the third bit sequence number from the left is
• the third bit sequence number from the left is
• n and m may be set dynamically according to the congestion state of the network. For example, in a congested state, bucket loss is likely to occur. Therefore, if n is increased and m is decreased, loss of priority information due to packet loss is unlikely to occur on the receiving device side.
• the packet loss detecting means 1713 of the third embodiment is important because of the interval determined from the number and time of packet reception and the mismatch of sequence numbers.
• the packet in the receive buffer ⁇ ⁇ the sequence number of the received packet and the priority information added by the priority information adding means of the transmitting device At the time of loss, the sequence number of the packet that can be determined to be retransmitted is detected.
• the receiving unit performs the same processing as that of the receiving unit of the second embodiment, but adds a process of updating the priority information template after receiving the packet to which the priority information is added.
• FIG. 19 is a flowchart for explaining an example of the flow of the packet loss detecting means of the receiving apparatus according to the third embodiment.
• FIG. 20 shows an example of the packet loss and the packet loss detecting means.
• the interval at which the packet loss detection means 1713 performs the packet loss detection processing is determined by the difference between the sequence number and time stamp of the last bucket that performed the previous packet loss detection processing and the sequence number and time stamp of the received packet. decide. Or every time a packet is lost.
• the interval between the sequence numbers at which the packet loss detection means performs packet loss processing is Nint
• the time stamp interval is Tint
• the sequence number of the last bucket that performed the previous packet loss detection means is Ncur
• the previous packet loss detection means was used.
• the interval at which the bucket loss detecting means 1713 performs the bucket loss detection processing is, for example, the sequence number or time stamp of the last bucket that performed the previous bucket loss detection processing and the sequence number or time stamp of the currently received packet. Determine from the difference.
• the interval between sequence numbers at which the packet loss detection means performs packet loss processing is Nint, the time stamp interval is Tint, and the sequence number of the last packet at which the packet loss detection means performed packet loss detection processing last time is Nint. If Ncur, the timestamp of the last bucket in which the packet loss detecting means performed the packet loss detection processing last time is Tcur, the sequence number of the packet received by the receiving means this time is equal to or greater than Ncur + Nint. If the value is greater than or the timestamp of the bucket received this time is equal to or greater than Tcur + Tint, substitute the sequence number and timestamp of the packet received this time into Ncr and Tcur, respectively. Then, packet loss detection processing (step S306) is performed.
• the packet loss detecting means 1713 determines the sequence number Ncur (the sequence number of the last packet of this time) from the next packet after the last packet for which the packet loss detection processing was previously performed in the reception buffer sorted in order of the sequence number. Sequence number in the range up to the packet (excluding the Ncur packet) or the range up to the packet with the time stamp Tcur (the time stamp of the last packet in this case) (excluding the Tcur packet). It checks the consistency and priority information of packets and detects the loss of high-priority packets to be retransmitted.
• FIG. 19 shows the detailed flow of the packet loss detection processing by the packet loss detection means 1713.
• packet loss detection unit 1713 began the sequence number in the receive buffer is: set the pointer equal path Kedzuto the FSN to P (step Sl902) o where, FSN is the last packet drop This is the sequence number of the next bucket after the last packet that was detected.
• Loss is the number of lost packets
• I is the distance from FSN
• SN list is the list of lost bucket sequence numbers with high priority to be retransmitted
• 0 is set as the initial value for Loss and FSN
• SN list To A blank (empty list) is set as the initial value (step S1903).
• step S1905 the sequence number of the last packet of the current packet from the packet next to the last packet in which the previous packet loss detection processing was performed
• Ncur the sequence number of the last packet of the current packet from the packet next to the last packet in which the previous packet loss detection processing was performed
• Ncur the sequence number of the last packet of the current packet from the packet next to the last packet in which the previous packet loss detection processing was performed
• the sequence number Dump Tcur the timestamp of the last packet this time
• step S1905 compares the sequence number of the packet stored in the pointer P of the reception buffer with FSN + I.
• step S1905 if the sequence numbers of the packets stored in the pointer P and FSN + I are the same, the packet of the sequence number FSN + I has been received without loss. Then, I is incremented (step S1906), and the point of the next packet is set in P (step S1908).
• step S1905 if the sequence number of the packet stored in FSN + I is not equal to the sequence number of the packet stored in Boyne P, the flow branches to step S1907. If FSN + I is smaller than the sequence number of the packet stored in the bus P (step S1907), the packet of sequence number FSN + I is lost, and the flow branches to step S1909. In step S1909, it is determined whether or not the priority information of the packet whose sequence number in the priority information table 2001 is FSN + I should be retransmitted (step S1909).
• FSN + I is added to SN_list to request retransmission of sequence number FSN + I.
• Step 1910 Increment I and Loss (1911). If it is determined from the priority information that the packet of sequence number FSN + I is a low-priority packet that does not require retransmission (step 1909), a retransmission request is not made. Increment I and Loss without adding the missing FSN + I to the SNJList (step S1911).
• the range indicated in step S1904 ie, the range from the packet following the last packet in which the previous packet loss detection processing was performed to the packet of sequence number Ncur (the sequence number of the last packet this time) (however, When the comparison of this sequence number is completed within the range up to the packet of the timestamp Tcur (the timestamp of the last packet of this time) (excluding the packet of Tcur), or the packet of the timestamp Tcur (excluding the packet of Tcur), In step S1912), I is added to the FSN (step 1913), and the FSN is set as the start sequence number of the next packet loss detection process (step S511). At this time, the number in the SN list is the sequence number of the lost packet within the range, and the loss is the number of the lost packet.
• FIG. 20 shows an example of the reception buffer in which a packet loss has occurred and the result of the packet loss detection processing.
• reference numeral 2001 denotes a priority information table in which a sequence number is associated with priority information assigned according to the importance of a packet having this sequence number.
• 2003 indicates the state of FSN, Ncur, I, Loss, Snjist at the time of the Nth packet loss detection processing
• 204 indicates N + Indicates the state of FSN, Ncur, I, Loss, Sn_list at the time of the first packet loss detection process.
• the sequence numbers of the buckets in the receive buffer 2002 are..., 8, 9, 10, 12, 15, 16, 18, 19, 22, 2 3, 2 4, 2 5, 2 6, etc.
• 1 means a packet having a high priority to be retransmitted
• 0 means a packet having a low priority which is not retransmitted.
• this packet Since the priority information of the packet with sequence number 21 is 1, this packet is a packet with a high priority to be retransmitted, and 21 is added to the SL list, but sequence numbers 17 and 20 are added. Since the priority information of this packet is 0, these packets are packets of low priority not to be retransmitted, and are not added to the SN_list because no retransmission request is made.
• the packet loss detection means If Loss> 0 after the packet loss detection means, the packet loss is detected, so the retransmission sequence number addition means issues a command to add the SNJist sequence number to the retransmission request list management means. Then, the packet providing means is the same means as in the second embodiment, but deletes priority information having a sequence number smaller than the sequence number of the last packet provided from the priority information table. According to the third embodiment, in addition to the effects of the first and second embodiments, by providing the priority information adding means, the total transmission amount is smaller than the case where the priority sequence number is provided for all the transmitted packets. On the other hand, the priority of the bucket that has been lost in the receiving device can be more accurately recognized in the receiving device.
• the retransmission request response packet by the retransmission request response means according to claim 5 is not required, and network waste and retransmission request response load of the transmission device can be reduced. Also, by adjusting the length and frequency of the priority information, there is an effect that even in a congested network, the loss of the priority information due to a packet loss on the receiving device side is less likely to occur.
• the packet retransmission system according to the present invention is suitable for performing more reliable communication with emphasis on real-time in transfer of data such as video and audio with high real-time. I have.

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